U.S. patent application number 13/612237 was filed with the patent office on 2013-11-14 for electrowetting display panel and method of manufacturing the same.
This patent application is currently assigned to SAMSUNG DISPLAY CO., LTD.. The applicant listed for this patent is Wonil CHOI, Wangsu HONG, Chanuk JON, Jaejin LYU, Jinbo SHIM, Gilhwan YEO. Invention is credited to Wonil CHOI, Wangsu HONG, Chanuk JON, Jaejin LYU, Jinbo SHIM, Gilhwan YEO.
Application Number | 20130301106 13/612237 |
Document ID | / |
Family ID | 49548397 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130301106 |
Kind Code |
A1 |
JON; Chanuk ; et
al. |
November 14, 2013 |
ELECTROWETTING DISPLAY PANEL AND METHOD OF MANUFACTURING THE
SAME
Abstract
An electrowetting display panel includes an array substrate, a
cover substrate, an electrowetting layer, and a hydrophobic
pattern. The array substrate includes a display area and a
peripheral area surrounding the display area and the cover
substrate faces the array substrate. The electrowetting layer is
disposed between the array substrate and the cover substrate and
includes a polar fluid as a first fluid and a non-polar fluid as a
second fluid. The hydrophobic pattern is disposed in the peripheral
area.
Inventors: |
JON; Chanuk; (Seoul, KR)
; YEO; Gilhwan; (Hwaseong-si, KR) ; SHIM;
Jinbo; (Seoul, KR) ; LYU; Jaejin; (Yongin-si,
KR) ; CHOI; Wonil; (Ansan-si, KR) ; HONG;
Wangsu; (Asan-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JON; Chanuk
YEO; Gilhwan
SHIM; Jinbo
LYU; Jaejin
CHOI; Wonil
HONG; Wangsu |
Seoul
Hwaseong-si
Seoul
Yongin-si
Ansan-si
Asan-si |
|
KR
KR
KR
KR
KR
KR |
|
|
Assignee: |
SAMSUNG DISPLAY CO., LTD.
YONGIN-CITY
KR
|
Family ID: |
49548397 |
Appl. No.: |
13/612237 |
Filed: |
September 12, 2012 |
Current U.S.
Class: |
359/290 ;
445/24 |
Current CPC
Class: |
G02B 26/005
20130101 |
Class at
Publication: |
359/290 ;
445/24 |
International
Class: |
G02B 26/00 20060101
G02B026/00; G02F 1/153 20060101 G02F001/153 |
Foreign Application Data
Date |
Code |
Application Number |
May 9, 2012 |
KR |
10-2012-0049086 |
Claims
1. An electrowetting display panel comprising: an array substrate
including a display area and a peripheral area surrounding the
display area; a cover substrate facing the array substrate; an
electrowetting layer disposed between the array substrate and the
cover substrate and including a polar fluid as a first fluid and a
non-polar fluid as a second fluid; and a hydrophobic pattern
disposed in the peripheral area.
2. The electrowetting display panel of claim 1, wherein the
hydrophobic pattern has a closed-loop shape surrounding the display
area.
3. The electrowetting display panel of claim 2, wherein the
hydrophobic pattern comprises one of an alkyl group-containing
compound, a fluorine-containing compound, and a silicon nano-wire
having an oxygen-adsorbed surface.
4. The electrowetting display panel of claim 3, wherein the
hydrophobic pattern and the first fluid have a contact angle equal
to or greater than about 150 degrees.
5. The electrowetting display panel of claim 3, wherein the array
substrate comprises: a first base substrate including a plurality
of pixel areas; and a partition wall disposed between the pixel
areas, wherein the hydrophobic pattern has a thickness smaller than
a thickness of the partition wall.
6. The electrowetting display device of claim 5, wherein the
thickness of the hydrophobic pattern is in a range of about 2
micrometers to about 10 micrometers.
7. The electrowetting display device of claim 2, wherein the
hydrophobic pattern comprises a mixture of one of a heat-curable
resin and a light-curable resin and one of an alkyl-containing
compound, a fluorine-containing compound and a silicon nano-wire
having an oxygen-adsorbed surface.
8. The electrowetting display device of claim 7, wherein the
hydrophobic pattern and the first fluid have a contact angle equal
to or greater than about 110 degrees.
9. The electrowetting display device of claim 2, further comprising
a sealing pattern having a closed-loop shape to surround the
display area, wherein the hydrophobic pattern is disposed between
the display area and the sealing pattern.
10. The electrowetting display device of claim 9, wherein the
hydrophobic pattern comprises a mixture of one of a heat-curable
resin and a light-curable resin and one of an alkyl-containing
compound, a fluorine-containing compound and a silicon nano-wire
having an oxygen-adsorbed surface.
11. The electrowetting display device of claim 10, wherein the
hydrophobic pattern and the first fluid have a contact angle equal
to or greater than about 110 degrees.
12. The electrowetting display device of claim 9, wherein the
hydrophobic pattern comprises one of a carbon nanotube sponge and a
hydrophobic polymer compound.
13. The electrowetting display device of claim 12, wherein the
hydrophobic pattern and the first fluid have a contact angle equal
to or greater than about 110 degrees.
14. A method of manufacturing an electrowetting display panel,
comprising: preparing an array substrate including a display area
and a peripheral area surrounding the display area; disposing a
hydrophobic pattern in the peripheral area; preparing a cover
substrate to face the array substrate; disposing an electrowetting
layer including a polar fluid as a first fluid and a non-polar
fluid as a second fluid in a space defined by the array substrate
and the hydrophobic pattern; and coupling the array substrate to
the cover substrate.
15. The method of claim 14, wherein the hydrophobic pattern
comprises a mixture of one of a heat-curable resin and a
light-curable resin and one of an alkyl-containing compound, a
fluorine-containing compound and a silicon nano-wire having an
oxygen-adsorbed surface.
16. The method of claim 15, wherein the hydrophobic pattern and the
first fluid have a contact angle equal to or greater than about 150
degrees.
17. The method of claim 14, wherein the array substrate comprises:
a first base substrate that including a plurality of pixel areas;
and a partition wall disposed between the pixel areas, and the
hydrophobic pattern has a thickness smaller than a thickness of the
partition wall.
18. The method of claim 14, wherein the hydrophobic pattern
comprises a mixture of one of a heat-curable resin and a
light-curable resin and one of an alkyl-containing compound, a
fluorine-containing compound and a silicon nano-wire having an
oxygen-adsorbed surface.
19. The method of claim 18, wherein the hydrophobic pattern and the
first fluid have a contact angle equal to or greater than about 110
degrees.
20. The method of claim 14, further comprising forming a sealing
pattern having a closed-loop shape surrounding the display area,
wherein the hydrophobic pattern is disposed between the display
area and the sealing pattern.
21. The method of claim 20, wherein the hydrophobic pattern
comprises a mixture of one of a heat-curable resin and a
light-curable resin and one of an alkyl-containing compound, a
fluorine-containing compound and a silicon nano-wire having an
oxygen-adsorbed surface.
22. The method of claim 20, wherein the hydrophobic pattern
comprises one of a carbon nanotube sponge and a hydrophobic polymer
compound.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from and the benefit of
Korean Patent Application No. 10-2012-0049086 filed on May 9, 2012,
which is hereby incorporated by reference for all purpose as if
fully set forth herein.
BACKGROUND
[0002] 1. Field of Disclosure
[0003] Exemplary embodiments of the present invention relate to
electrowetting display panel and a method of manufacturing the
same. More particularly, exemplary embodiments of the present
invention relate to an electrowetting display panel capable of
reducing electrolyte loss and a method of manufacturing the
electrowetting display panel.
[0004] 2. Description of the Related Art
[0005] An electrowetting display panel is showing much potential as
a next generation display device because of its various desirable
properties, such as fast response speed, low driving voltage, slim
size, etc.
[0006] An electrowetting display panel displays images by using an
electrowetting phenomenon that causes a fluid to move in response
to a voltage being applied to the fluid. The voltage changes the
surface tension of the fluid, which in turn makes the fluid move or
changes its "shape." The fluid is controlled using a relatively low
voltage, and thus power consumption is low.
[0007] An electrowetting layer for the electrowetting display panel
is manufactured by loading an array substrate and a cover substrate
into an electrolyte bath and coupling the array substrate and the
cover substrate. During this process, a large electrolyte bath is
required and a large amount electrolyte solution is wasted.
SUMMARY
[0008] Exemplary embodiments of the present invention relate an
electrowetting display panel capable of reducing loss in amount of
electrolyte.
[0009] Exemplary embodiments of the present invention relate a
method of manufacturing the electrowetting display panel.
[0010] Additional features of the invention will be set forth in
the description which follows, and in part will be apparent from
the description, or may be learned by practice of the
invention.
[0011] An exemplary embodiment of the present invention discloses
an electrowetting display panel includes an array substrate,
opposite cover substrate, an electrowetting layer, and a
hydrophobic pattern. The array substrate includes a display area
and a peripheral area surrounding the display area and the cover
substrate faces the array substrate. The electrowetting layer is
disposed between the array substrate and the cover substrate and
includes a polar fluid as a first fluid and a non-polar fluid as a
second fluid. The hydrophobic pattern is disposed in the peripheral
area.
[0012] The hydrophobic pattern may include one of an alkyl
group-containing compound, a fluorine-containing compound, and a
silicon nano-wire having an oxygen-adsorbed surface, and the
hydrophobic pattern and the first fluid have a contact angle equal
to or greater than about 150 degrees.
[0013] The array substrate may include a first base substrate that
includes a plurality of pixel areas and a partition wall disposed
between the pixel areas, and the hydrophobic pattern has a
thickness smaller than a thickness of the partition wall.
[0014] The hydrophobic pattern may include a mixture of one of a
heat-curable resin and a light-curable resin and one of an
alkyl-containing compound, a fluorine-containing compound and a
silicon nano-wire having an oxygen-adsorbed surface.
[0015] The electrowetting display device may further include a
sealing pattern having a closed-loop shape to surround the display
area, and the hydrophobic pattern is disposed between the display
area and the sealing pattern.
[0016] An exemplary embodiment of the present invention discloses a
method of manufacturing an electrowetting display panel includes
preparing an array substrate that includes a display area and a
peripheral area surrounding the display area, disposing a
hydrophobic pattern in the peripheral area, preparing opposite
cover substrate to face the array substrate, disposing an
electrowetting layer that includes a first fluid as a polar fluid
and a second fluid as a non-polar fluid in a space defined by the
array substrate and the hydrophobic pattern, and coupling the array
substrate to the cover substrate.
[0017] According to the above, the electrowetting display panel may
include the hydrophobic pattern, and thus the electrowetting
display panel may reduce loss in amount of electrolyte.
[0018] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention, and together with the description serve to explain
the principles of the invention:
[0020] FIG. 1 is a block diagram showing an electrowetting display
device according to an exemplary embodiment of the present
invention;
[0021] FIG. 2 is a partially cut-away perspective view showing an
electrowetting display panel of the electrowetting display device
shown in FIG. 1;
[0022] FIG. 3 is a plan view showing the electrowetting display
panel shown in FIG. 2;
[0023] FIGS. 4 and 5 are cross-sectional views explaining an
operation of the electrowetting display panel taken along a line
I-I' of FIG. 3;
[0024] FIG. 6 is a cross-sectional view taken along a line II-II'
of FIG. 3;
[0025] FIGS. 7, 8, and 10 are cross-sectional views explaining a
method of manufacturing the electrowetting display panel shown in
FIG. 1;
[0026] FIG. 9 is a partially enlarged view showing a portion "A" of
FIG. 8;
[0027] FIGS. 11 and 12 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention;
[0028] FIGS. 13 and 14 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention; and
[0029] FIGS. 15 and 16 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention.
DETAILED DESCRIPTION
[0030] The invention is described more fully hereinafter with
reference to the accompanying drawings, in which embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure is thorough, and will fully convey
the scope of the invention to those skilled in the art. In the
drawings, the size and relative sizes of layers and regions may be
exaggerated for clarity. Like reference numerals in the drawings
denote like elements.
[0031] It will be understood that when an element or layer is
referred to as being "on", "connected to" or "coupled to" another
element or layer, it can be directly on, connected or coupled to
the other element or layer or intervening elements or layers may be
present. In contrast, when an element is referred to as being
"directly on," "directly connected to" or "directly coupled to"
another element or layer, there are no intervening elements or
layers present. Like numbers refer to like elements throughout. As
used herein, the term "and/or" includes any and all combinations of
one or more of the associated listed items. It will be understood
that for purposes of this disclosure, "at least one of X, Y, and Z"
can be construed as X only, Y only, Z only, or any combination of
two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ).
[0032] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another region,
layer or section. Thus, a first element, component, region, layer
or section discussed below could be termed a second element,
component, region, layer or section without departing from the
teachings of the present invention.
[0033] Spatially relative terms, such as "beneath", "below",
"lower", "above", "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
exemplary term "below" can encompass both an orientation of above
and below. The device may be otherwise oriented (rotated 90 degrees
or at other orientations) and the spatially relative descriptors
used herein interpreted accordingly.
[0034] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms, "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "includes" and/or "including", when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0035] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0036] Hereinafter, exemplary embodiments of the present invention
will be explained in detail with reference to the accompanying
drawings.
[0037] FIG. 1 is a block diagram showing an electrowetting display
device according to an exemplary embodiment of the present
invention.
[0038] Referring to FIG. 1, the electrowetting display device
includes a timing controller 10, a data driver 20, a scan driver
30, a voltage generator 40, and an electrowetting display panel 50.
The electrowetting display panel 50 is driven by the timing
controller 10, the data driver 20, the scan driver 30, and the
voltage generator 40.
[0039] Responsive to a first gray-scale data signal DG1 and a first
control signal C1 from an external source, e.g., a graphic
controller, the timing controller 10 applies a second gray-scale
data signal DG2 and a second control signal C2 to the data driver
20, applies a third control signal C3 to the scan driver 30, and
applies a fourth control signal C4 to the voltage generator 40.
[0040] The data driver 20 converts the second gray-scale data
signal DG2 to gray-scale voltages, i.e., data signals, and applies
the data signals D1, . . . , Dp-1, Dp, Dp+1, . . . , Dm to the
electrowetting display panel 50.
[0041] The scan driver 30 sequentially applies scan signals S1, . .
. , Sq-1, Sq, . . . , Sn to the electrowetting display panel 50 in
response to the third control signal C3.
[0042] The voltage generator 40 applies a common voltage Vcom to
the electrowetting display panel 50 in response to the fourth
control signal C4. Although not shown in figures, the voltage
generator 40 generates various voltages required by the timing
controller 10, the data driver 20, and the scan driver 30.
[0043] The electrowetting display panel 50 includes m data lines
DL, i.e., source lines, to transmit the data voltages and n gate
lines SL, i.e., scan lines, to transmit a gate-on signal.
[0044] Pixel areas are positioned adjacent to crossing points of
the data lines DL and the gate lines SL crossing the data lines DL.
Each pixel area includes a thin film transistor 52, a pixel
electrode 120, and a partition wall 150. The thin film transistor
52 includes a gate electrode electrically connected to a
corresponding scan line of the scan lines SL, a source electrode
electrically connected to a corresponding data line of the data
lines, and a drain electrode (not shown) electrically connected to
the pixel electrode 120.
[0045] The partition wall 150 surrounds the pixel electrode 120 to
define a predetermined area, and a conductive coloring liquid (or a
conductive water drop) is accommodated in the predetermined area.
The conductive coloring liquid is dispersed or united in response
to an electric potential difference between voltages respectively
applied to the pixel electrode 120 disposed under the conductive
coloring liquid and a common electrode (not shown) disposed above
the conductive coloring liquid. The common electrode is applied
with the common voltages Vcom.
[0046] FIG. 2 is a partially cut-away perspective view showing an
electrowetting display panel of the electrowetting display device
shown in FIG. 1, and FIG. 3 is a plan view showing the
electrowetting display panel shown in FIG. 2. FIGS. 4 and 5 are
cross-sectional views explaining an operation of the electrowetting
display panel taken along a line I-I' of FIG. 3, and FIG. 6 is a
cross-sectional view taken along a line II-IF of FIG. 3.
[0047] Referring to FIGS. 2 to 6, the electrowetting display panel
50 of the electrowetting display device includes an array substrate
100 that includes a display area DA and a peripheral area PA, a
cover substrate 200 facing the array substrate 100, an
electrowetting layer 300 disposed between the array substrate 100
and the cover substrate 200, a sealing pattern 400 that couples the
array substrate 100 and the cover substrate 200 to prevent the
electrowetting layer 300 from leaking, and a first hydrophobic
pattern 500 disposed between the sealing pattern 400 and the
display area DA.
[0048] The array substrate 100 includes a first base substrate 110
on which a plurality of pixel areas PX is arranged, the pixel
electrode 120 arranged in each pixel area PX, an insulating layer
130 that covers the pixel electrode 120, a hydrophobic layer 140
disposed on the insulating layer 130, and the partition wall 150
disposed between the pixel areas PX.
[0049] In addition, the pixel areas PX are arranged in the display
area DA of the first base substrate 100 in a matrix form. The
peripheral area PA surrounds the display area DA, and circuits,
such as the timing controller 10, the data driver 20, the scan
driver 30, and the voltage generator 40 are arranged in the
peripheral area PA. In addition, each pixel area PX includes the
gate line SL exteningd in a first direction D1 substantially
parallel to a side of the array substrate 100 and a data line DL
extending in a second direction substantially perpendicular to the
first direction. Accordingly, the data line DL is insulated from
and crosses the gate line SL. In addition, each pixel area PX
includes the thin film transistor 52 electrically connected to the
gate line SL and the data line DL.
[0050] The first base substrate 110 may be formed of a transparent
insulating material, e.g., a polymer such as glass or plastic. When
the first base substrate 110 is a plastic substrate, the first base
substrate 110 may include polyethylene terephthalate (PET), fiber
reinforced plastic (FRP), or polyethylene naphthalate (PEN). In
addition, the first base substrate 110 is a hard or flexible
substrate.
[0051] When the electrowetting display panel 50 is a transmission
type, the pixel electrode 120 may have a single-layer structure of
a transparent conductive material, such as indium tin oxide (ITO)
or indium zinc oxide (IZO). In addition, when the electrowetting
display panel 50 is a reflection type, the pixel electrode 120 may
have a multi-layer structure. For instance, in some embodiments,
the pixel electrode 120 includes a first conductive layer (not
shown) disposed in each pixel PX and connected to the thin film
transistor 52 and a second conductive layer (not shown) disposed on
the first conductive layer. In this case, one of the first
conductive layer and the second conductive layer includes the
transparent conductive oxide such as indium tin oxide or indium
zinc oxide. Further, the other one of the first conductive layer
and the second conductive layer includes a metal material with
conductivity to reflect light from an external source (hereinafter,
referred to as external light).
[0052] The insulating layer 130 includes an insulating material
through which the light transmits. For example, the insulating
layer 130 may include silicon oxide material or silicon nitride
material. In addition, when the electrowetting display panel 50 is
the reflection type, the insulating layer 130 includes a material
that reflects the external light. For instance, the insulating
layer 130 includes a white photoresist that reflects the external
light. The insulating layer 130 has a single-layer structure or a
multi-layer structure, or may be omitted.
[0053] The hydrophobic layer 140 includes at least one hydrophobic
organic resin selected from the group consisting of fluoropolymer,
polyxylene-based resin, polypropylene-based resin, siloxane-based
resin, and combination thereof and at least one hydrophobic
inorganic particle selected from the group consisting of SiO.sub.2,
Al.sub.2O.sub.3, ZnO, TiO.sub.2, BST (Barium Strontium Titanate),
and combination thereof. The hydrophobic layer 140 may be
transparent when the electrowetting display panel 50 is the
transmission type. In addition, when the electrowetting display
panel 50 is the reflection type, the hydrophobic layer 140 has a
white color and reflects a specific wavelength of the external
light, thereby displaying a desired color.
[0054] The partition wall 150 is disposed on the hydrophobic layer
140 to provide the space defined by the first base substrate 110
and the partition wall 150. The space may correspond to a pixel
area PX. Thus, a range of the pixel area PX is limited by the
partition wall 150. In the present exemplary embodiment, the
partition wall 150 is disposed on the first base substrate 110 and
defines the pixel area PX with the partition wall 150. However,
pixel area PX is not limited to being defined in this manner. For
instance, in some embodiments, the pixel area PX may be defined by
the first base substrate 110, the cover substrate 200, and the
partition wall 150.
[0055] The cover substrate 200 includes a second base substrate 210
and the common electrode 220 facing the pixel electrode 120. In
addition, the cover substrate 200 may further include an insulating
layer (not shown) that covers the common electrode 220 and has a
hydrophilic surface.
[0056] The second base substrate 210 may be formed of the same
material as the first base substrate 110. That is, the second base
substrate 210 may be a transparent insulating material, such as
glass, plastic, etc.
[0057] The common electrode 220 receives the common voltage and is
formed of the transparent conductive material, such as indium tin
oxide, indium zinc oxide, etc. so as to allow the external light
from the second base substrate 210 to travel to the electrowetting
layer 300.
[0058] The electrowetting layer 300 is accommodated in the pixel
area PX defined by the partition wall 150 and the first base
substrate 110 or the second base substrate 210. The electrowetting
layer 300 includes a first fluid 310 and a second fluid 320. The
first fluid 310 and the second fluid 320 have different specific
gravities from each other and are not mixed with each other. For
example, the second fluid 320 may have a specific gravity greater
than the specific gravity of the first fluid 310.
[0059] In addition, one of the first fluid 310 and the second
fluid, e.g., the first fluid 310, may be a polar fluid and the
other a non-polar fluid. In one embodiment, the first fluid 310 is
a polar fluid such as an electrolyte solution (e.g., a mixture of
water and ethyl alcohol) in which potassium chloride is dissolved.
The first fluid 310 transmits light. The second fluid 320 may be
non-polar oil (e.g., silicon oil) and include a black dye or a
material absorbing the external light so as to serve a light
shutter that blocks or transmits the external light. In addition,
the second fluid 320 includes a color dye to reflect the specific
wavelength of the external light.
[0060] The sealing pattern 400 is disposed in the peripheral area
PA and has a closed-loop shape surrounding the display area DA. The
sealing pattern 400 maintains a gap between the array substrate 100
and the cover substrate 200 and prevents the electrowetting layer
300 from leaking. In addition, the sealing pattern 400 may include
a heat-curable resin or a light-curable resin.
[0061] The first hydrophobic pattern 500 is disposed between the
display area DA and the sealing pattern 400 and has a closed-loop
shape surrounding the display area DA. In addition, the first
hydrophobic pattern 500 has a thickness smaller than a thickness of
the partition wall 150. In detail, the first hydrophobic pattern
500 has the thickness of about 2 micrometers to about 10
micrometers. Accordingly, the first hydrophobic pattern 500 forms a
predetermined space together with the array substrate 100.
[0062] The first hydrophobic pattern 500 has super-hydrophobicity
and has a contact angle with respect to the polar fluid of about
150.degree. or more. The first hydrophobic pattern 500 includes an
alkyl group-containing compound, e.g., at least one of alkyl ketone
dimer (AKD), dialkyl ketone (DAK), and alkyl silane. In addition,
the first hydrophobic pattern 500 may include a
polytetrafluoro-ethylene (PTFE) that contains fluorine. Further,
the first hydrophobic pattern 500 may include a silicon nano-wire
having an oxygen-adsorbed surface.
[0063] Hereinafter, an operation of the electrowetting display
device will be described in detail.
[0064] In the case that the voltages are not applied to the pixel
electrode 120 and the common electrode 220, no electric potential
difference occurs between the pixel electrode 120 and the common
electrode 220, and thus the change of interfacial tension does not
exist between the first fluid 310 and the second fluid 320. In this
case, since the hydrophobic layer 140 has hydrophobicity or
liphophilicity, the second fluid 320 is uniformly dispersed on the
hydrophobic layer 140 as shown in FIG. 4. In addition, the second
fluid 320 includes the black dye or the material absorbing the
light, and thus the second fluid 320 blocks or absorbs the external
light. Accordingly, the electrowetting display device is in a dark
state.
[0065] When voltages are respectively applied to the pixel
electrode 120 and the common electrode 220, an electric potential
difference forms between the pixel electrode 120 and the common
electrode 220, a change of the interfacial tension is caused
between the first fluid 310 and the second fluid 320. Where the
first fluid 310 is the polar fluid, the second fluid 320 moves to
an area adjacent to the partition wall 150 as shown in FIG. 5. This
leaves the first fluid 310 covering the pixel areas PX so that the
electrowetting display panel 50 is in a state in which the external
light passes through the electrowetting display panel 50.
Accordingly, when the electrowetting display panel 50 is the
reflection type, the external light passes through the cover
substrate 200 and the electrowetting layer 300, is reflected by the
pixel electrode 120 or the insulating layer 130, and passes through
the electrowetting layer 300 again to travel to the outside of the
electrowetting display panel 50. Therefore, the electrowetting
display device is in a bright state.
[0066] Meanwhile, when the electrowetting display panel 50 is the
transmission type, the external light may be provided to the
electrowetting display panel 50 through the backlight unit (not
shown). The external light provided to the electrowetting display
panel 50 sequentially passes through the array substrate 100, the
electrowetting layer 300, and the cover substrate 200 and travels
to the outside of the electrowetting display panel 50. Thus, the
electrowetting display device is in the bright state.
[0067] FIGS. 7, 8, and 10 are cross-sectional views explaining a
method of manufacturing the electrowetting display panel shown in
FIG. 1 and FIG. 9 is a partially enlarged view showing a portion
"A" of FIG. 8.
[0068] Referring to FIG. 7, the pixel electrode 120 is formed on
the first base substrate 110, in which the pixel areas are defined,
to correspond to each pixel area.
[0069] The first base substrate 110 includes the display area DA in
which the pixel areas are arranged in a matrix form and the
peripheral area PA surround the display area DA. The first base
substrate 110 is formed of a transparent insulating material.
[0070] When the electrowetting display panel 50 is the transmission
type, the pixel electrode 120 may have the single-layer structure
of the transparent conductive material. In addition, when the
electrowetting display panel 50 is the reflection type, the pixel
electrode 120 may have the multi-layer structure of the transparent
conductive layer and the conductive reflective layer. Further, the
pixel electrode 120 is electrically connected to the thin film
transistor disposed in each pixel of the first base substrate
110.
[0071] After the pixel electrode 120 is formed, the insulating
layer 130 is formed to cover the pixel electrode 120. The
insulating layer 130 may include an insulating material that
transmits light, e.g., silicon nitride material or silicon oxide
material. In addition, when the electrowetting display panel 50 is
the reflection type, the insulating layer 130 includes the white
photoresist that reflects external light.
[0072] Then, the hydrophobic layer 140 is formed on the insulating
layer 130. The hydrophobic layer 140 includes at least one
hydrophobic organic resin selected from the group consisting of
fluoropolymer, polyxylene-based resin, polypropylene-based resin,
siloxane-based resin, and combination thereof and at least one
hydrophobic inorganic particle selected from the group consisting
of SiO.sub.2, Al.sub.2O.sub.3, ZnO, TiO.sub.2, BST (Barium
Strontium Titanate), and combination thereof.
[0073] When the hydrophobic layer 140 is formed, the partition wall
150 is formed on the hydrophobic layer 140. The partition layer 150
surrounds the pixel electrode 120 to form the space defined by the
first base substrate 110 and the partition wall 150. The space may
correspond to each pixel area PX.
[0074] After that, the sealing pattern 400 is formed in the
peripheral area PA to have a closed-loop shape surrounding the
display area DA. The sealing pattern 400 may include the
heat-curable resin or the light-curable resin and may be formed by
using a squeeze method or an inkjet method.
[0075] Then, the first hydrophobic pattern 500 is formed between
the display area DA and the sealing pattern 400. The first
hydrophobic pattern 500 has a closed-loop shape surrounding the
display area DA. The first hydrophobic pattern 500 has
super-hydrophobicity and has a contact angle with respect to the
polar fluid of about 150.degree. or more.
[0076] The first hydrophobic pattern 500 has super-hydrophobicity
and forms a predetermined space together with the array substrate
100, and thus the polar fluid is accommodated in the area
surrounded by the first hydrophobic pattern 500 on the array
substrate 100.
[0077] Referring to FIG. 8, after the first hydrophobic pattern 500
is formed, the second fluid 320, which is the non-polar fluid, is
accommodated in the space formed by the first base substrate 110
and the partition wall 150, which corresponds to each pixel area
PX. Then, the first fluid 310, which is the polar fluid, is
accommodated in the space defined by the first hydrophobic pattern
500 and the array substrate 100. In this case, the first fluid 310
has a contact angle .theta.c equal to or greater than about 150
degrees with respect to the first hydrophobic pattern 500.
[0078] Since the first fluid 310 has a surface tension, the first
fluid 310 may exist only in the space defined by the first
hydrophobic pattern 500 and the array substrate 100.
[0079] After the first fluid 310 and the second fluid 320 are
accommodated, the cover substrate 200 is prepared by disposing the
common electrode 220 on the second base substrate 210. The cover
substrate 200 is disposed such that the common electrode 220 faces
the pixel electrode 120 of the array substrate 100.
[0080] Referring to FIG. 10, after preparing the cover substrate
200, the array substrate 100 and the cover substrate 200 are
coupled to each other. The array substrate 100 and the cover
substrate 200 are coupled to each other by the sealing pattern
400.
[0081] In FIG. 8, which depicts the state of the electrowetting
layer 300 before the cover substrate 200 is coupled, shows that the
level of the first fluid 310 is higher than the height of the
hydrophobic pattern 500. In spite of this excess fluid level, there
is hardly any spillage because the hydrophobic nature of the
pattern 500 keeps the polar first fluid 310 inside the area defined
by the sealing pattern 400. When the cover substrate 200 is coupled
as shown in FIG. 10, it pushes down on the upper portion of the
first fluid 310 and forces it into the space between the
hydrophobic pattern 500 and the sealing pattern 400. Without the
hydrophobic pattern 500, there would be spillage of the
electrowetting layer 300 outside the boundaries of the sealing
pattern 400, wasting the first fluid 310 and creating a mess.
[0082] When the array substrate 100 and the cover substrate 200 are
coupled to each other, the sealing pattern 400 is cured. The
sealing pattern 400 may be cured by heating the sealing pattern 400
when the sealing pattern 400 includes the heat-curable resin. In
addition, when the sealing pattern 400 includes the light-curable
resin, a visible ray or an ultraviolet ray is irradiated to the
sealing pattern 400 in accordance with the light-curable resin,
thereby curing the sealing pattern 400.
[0083] Hereinafter, various electrowetting display devices
according to another exemplary embodiment of the present invention
will be described with reference to FIGS. 11 to 16. In FIGS. 11 to
16, the same reference numerals denote the same elements in FIGS. 1
to 10, and thus detailed descriptions of the same elements will be
omitted in order to avoid redundancy.
[0084] FIGS. 11 and 12 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention.
[0085] The electrowetting display panel according to another
exemplary embodiment includes a sealing pattern 400 disposed in the
peripheral area PA and a second hydrophobic pattern 600 disposed
between the sealing pattern 400 and the display area DA.
[0086] Referring to FIG. 11, an array substrate 100 is prepared.
The array substrate 100 includes a first base substrate 110 in
which a plurality of pixel areas PX is defined, a pixel electrode
120 disposed in each pixel area PX, an insulating layer 130 that
covers the pixel electrode 120, a hydrophobic layer 140 disposed on
the insulating layer 130, and a partition wall 150 disposed between
the pixel areas PX. The pixel areas PX are arranged in the display
area DA in a matrix form and the peripheral area PA surrounds the
display area DA.
[0087] After the array substrate 100 is prepared, the sealing
pattern 400 is disposed in the peripheral area PA to have a
closed-loop shape surrounding the display area DA.
[0088] Then, the second hydrophobic pattern 600 is formed between
the display area DA and the sealing pattern 400. In this case, the
second hydrophobic pattern 600 may have a closed-loop shape to
surround the display area DA. In addition, the second hydrophobic
pattern 600 includes the same material and hydrophobic material as
those of the sealing pattern 400. For instance, the second
hydrophobic pattern 600 includes a mixture of one of heat-curable
resin and light-curable resin and one of an alkyl-containing
compound, a fluorine-containing compound and a silicon nano-wire
having an oxygen-adsorbed surface. The second hydrophobic pattern
600 has a contact angle with respect to the polar fluid, i.e., the
first fluid 310, of about 110.degree. or more.
[0089] After the second hydrophobic pattern 600 is formed, the
second fluid 320, which is the non-polar fluid, is accommodated in
the space surrounded by the first base substrate 110 and the
partition wall 150, which corresponds to each pixel area PX. Then,
the first fluid 310, which is the polar fluid, is accommodated in
the space defined by the second hydrophobic pattern 600 and the
array substrate 100.
[0090] After the first fluid 310 and the second fluid 320 are
disposed on the array substrate 100, the cover substrate 200 is
prepared and disposed such that the common electrode 220 of the
cover substrate 200 faces the pixel electrode 120 of the array
substrate 100.
[0091] Referring to FIG. 12, the array substrate 100 and the cover
substrate 200 are coupled to each other. The array substrate 100
and the cover substrate 200 are coupled to each other by the
sealing pattern 400 and the second hydrophobic pattern 600, which
are of approximately the same height in the embodiment that is
shown. As a result, the coupling force between the array substrate
100 and the cover substrate 200 may be stronger than that when the
array substrate 100 and the cover substrate 200 are coupled to each
other using only the sealing pattern 400.
[0092] When the array substrate 100 and the cover substrate 200 are
coupled to each other, the sealing pattern 400 and the second
hydrophobic pattern 600 are cured.
[0093] FIGS. 13 and 14 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention.
[0094] The electrowetting display panel according to another
exemplary embodiment includes a sealing pattern 400 disposed in the
peripheral area PA and a third hydrophobic pattern 700 disposed
between the sealing pattern 400 and the display area DA.
[0095] Referring to FIG. 13, an array substrate 100 is prepared.
The array substrate 100 includes a first base substrate 110 in
which a plurality of pixel areas PX is defined, a pixel electrode
120 disposed in each pixel area PX, an insulating layer 130 that
covers the pixel electrode 120, a hydrophobic layer 140 disposed on
the insulating layer 130, and a partition wall 150 disposed between
the pixel areas PX.
[0096] After the array substrate 100 is prepared, the sealing
pattern 400 is disposed in the peripheral area PA to have a
closed-loop shape surrounding the display area DA.
[0097] Then, the third hydrophobic pattern 700 is formed between
the display area DA and the sealing pattern 400. In this case, the
third hydrophobic pattern 700 may have a closed-loop shape to
surround the display area DA and have a thickness greater than that
of the sealing patter 400. In addition, the third hydrophobic
pattern 700 includes an elastic material and a hydrophobic material
or includes a material having elastic and hydrophobic properties.
In detail, the third hydrophobic pattern 700 includes a carbon
nanotube sponge or a hydrophobic polymer compound. The third
hydrophobic pattern 700 has a contact angle with respect to the
polar fluid, i.e., the first fluid 310, of about 110.degree. or
more.
[0098] After the third hydrophobic pattern 700 is formed, the first
fluid 310 and the second fluid 320 are disposed on the array
substrate 100 After that, the cover substrate 200 is prepared and
disposed such that the common electrode 220 of the cover substrate
200 faces the array substrate 100.
[0099] Referring to FIG. 14, the array substrate 100 and the cover
substrate 200 are coupled to each other, and then the sealing
pattern 400 and the third hydrophobic pattern 700 are cured.
[0100] FIGS. 15 and 16 are cross-sectional views explaining a
method of manufacturing an electrowetting display panel according
to another exemplary embodiment of the present invention.
[0101] The electrowetting display panel according to another
exemplary embodiment includes a fourth hydrophobic pattern 800
disposed in the peripheral area PA and used to couple the array
substrate 100 and the cover substrate 200.
[0102] Referring to FIG. 15, the array substrate 100 is prepared.
The array substrate 100 includes a first base substrate 110 in
which a plurality of pixel areas PX is defined, a pixel electrode
120 disposed in each pixel area PX, an insulating layer 130 that
covers the pixel electrode 120, a hydrophobic layer 140 disposed on
the insulating layer 130, and a partition wall 150 disposed between
the pixel areas PX.
[0103] After the array substrate 100 is prepared, the fourth
hydrophobic pattern 800 is disposed in the peripheral area PA to
have a closed-loop shape surrounding the display area DA. In the
present exemplary embodiment, the fourth hydrophobic pattern 800
may include the same material and hydrophobic material as those of
a conventional sealing pattern. In detail, the fourth hydrophobic
pattern 800 includes a mixture of one of heat-curable resin and
light-curable resin and one of an alkyl-containing compound, a
fluorine-containing compound and a silicon nano-wire having an
oxygen-adsorbed surface. The fourth hydrophobic pattern 800 has a
contact angle with respect to the polar fluid, i.e., the first
fluid 310, of about 110.degree. or more.
[0104] After the fourth hydrophobic pattern 800 is disposed, the
first fluid 310 and the second fluid 320 are disposed on the array
substrate 110. Then, the cover substrate 200 is prepared and
disposed such that the common electrode 220 of the cover substrate
200 faces the array substrate 100.
[0105] Referring to FIG. 16, the array substrate 100 and the cover
substrate 200 are coupled to each other. The array substrate 100
and the cover substrate 200 are coupled to each other by using the
fourth hydrophobic pattern 800. Accordingly, although a separate
hydrophobic pattern is not prepared, the array substrate 100 and
the cover substrate 200 are coupled to each other by the fourth
hydrophobic pattern 800 having hydrophobicity.
[0106] When the array substrate 100 and the cover substrate 200 are
coupled to each other, heat is applied to or light is irradiated to
the fourth hydrophobic pattern 800, thereby curing the fourth
hydrophobic pattern 800 are cured.
[0107] Although the exemplary embodiments of the present invention
have been described, it is understood that the present invention
should not be limited to these exemplary embodiments but various
changes and modifications can be made by one ordinary skilled in
the art within the spirit and scope of the present invention as
hereinafter claimed.
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